All-position rotary jet switch



May 7, l957 J. w. ooTHERTs 2,791,650

ALL-POSITION ROTARY JET SWITCH Filed Sept. 4, 1956 www ALL-POSITION RCTARY JET SWITCH Jerome W. Gootherts, Redwood City, Calif., assignor to Detroit Controls Corporation, Detroit, Mieli., a corporation of Michigan Application September 4, 1956, Serial No. 607,793

2 Claims. (Cl. 200-32) This invention relates to a rotary jet switch, and in general has for its object the provision of a switch of this type operable in any position and unaffected by accelerations of magnitudes such as encountered in aircraft.

More speciiicially, the object of this invention is the provision of an all-position rotary jet switch, including a casing provided with first and second spaced, parallel, annular channels circumscribing and in open communication with a central coaxial chamber; a rotor journaled in said central chamber coaxially therewith and provided with an internal annular mercury recess; an outwardly extending nozzle mounted on said rotor in communication with said recess; a ring of spaced contact terminals mounted on the peripheral wall of said central chamber adjacent the locus of said nozzle and in alignment therewith; first and second mercury slinger discs mounted on said rotor and extending respectively into said first and second annular channels; and a conduit extending between the peripheral edges of said first and second annular channels and communicating with said annular recess.

A further object of this invention is the provision of a switch of the character above described wherein its said contact terminals extend through s-aid casing so that they can be contacted with a suitable harness.

The invention possesses other advantageous features, some of which, with the foregoing, will be set forth at length in the following description where that form of the invention which has been selected for illustration in the `drawing accompanying land forming a part of the present specification, is outlined in full. In said drawing, one form of the invention is shown, but it is to be understood that it is not limited to such form, since the invention as set forth in the claims may be embodied in other forms.

In the accompanying drawing, the single gure therein illustrated is a vertical mid-section of a switch embodying the objects of my invention.

The switch as illustrated in this figure includes -a casing generally designated by the reference numeral 1 and preferably made of a central stepped ring 2, a baseplate 3, and cap 4 secured thereto by screws 5. Formed on the central ring 2 is an inwardly extending central annular ange 6 having inclined walls 7 and 8. As here illustrated, the ring 2, baseplate 3, and cap 4 are made of a dielectric material. These three members define a pair of spaced, parallel, annular, coaxial channels 9 and 11 merging and circumscribing a coaxial central chamber 12.

Mounted in the baseplate 3, coaxially therewith and extending upwardly within the lower confines of the chamber 12, is a stepped metal bearing bushing 13, and seated therein is an antifriction bearing 14 held in place by a snap ring 15. Mounted in the cap 4 coaxially with the antifriction bearing 14 is an -antifriction bearing 16 likewise held in place by a snap ring 17.

Journaled in the antifriction bearings 14 and 16 is a 2,791,650 Patented May 7, 1957 "ice shaft 18. Recessed within the bearing bushing 13 and surrounding the shaft 18 is a packing ring 19, and threaded to the top of the bearing bushing is a ring or nut 21 for compressing the packing ring 19. Similarly recessed in the cap 4 is a packing ring 22 maintained under proper pressure by a ring or nut 23 threaded into the lower end of the cap.

Secured to the shaft 18 by a pin 24 is a rotor 2S formed on its lower end with a recess for accommodating the upper end of the bearing bushing 13 with moderate clearance and provided with an inclined annular mercury recess 26.

Afxed respectively to the upper and lower ends of the rotor 25 by screws 27 are mercury slinger discs 28 and 29, the marginal portions of which are accommodated within the annular channels 9 and 11. p.

Mounted on the rotor 25 is an inclined, radially extending nozzle 31 communicating with the annular rotor recess 26 and provided with a generally downwardly directed orifice 32.

Extending through the casing ring 2, radially thereof, is a plurality of perip'herally spaced pins 33, the inner ends of these pins extending into the central chamber 12 and terminating at points adjacent the locus of the nozzle 31 and its orifice 32. The inner ends of the pins 33 therefore serve as contact terminals and their outer ends as means for connecting the contact terminals to a suitable harness. Here it should be noted that any number of pins 33 may be used, such as for example, in the order of 120.

interconnecting the peripheral edges of the annular channels 9 and 12 is a conduit or passageway 34. Formed in the bearing bushing 13 i-s an annular channel 35 and an upstanding passageway 36 communicating with the rotor recess 26 through a restricted opening 37. Establishing communication between the passageway 34 and the annular channel 35 is a conduit or passageway 38.

Formed in the upper face of the cap 4 is a lling well 39 normally closed by a screw 41.

Provided in the lower face of the baseplate 3 is a recess 42 communicating with a radial passageway 43, and extending therethrough is an electric lead 44 secured at its inner end to the bearing bushing 13 by a terminal screw 45.

As a result of this type of construction, the unit can be readily made liquid light, for there is no trouble in making the required seals between the casing elements 2, 3, and 4, between the casing element 3 and the bearing bushing 13, and between the shaft 18 and the bearing bushing and the casing cap 4. If desired, other equivalent seal-s, such as labyrinth seals, may be used in connection with these latter elements.

To place this switch in operation, the required connections are made to the lead wire and to the pins 33, and a small quantity of mercury is inserted into the switch through the well 39. Here it is also assumed that the shaft 18 has been connected to a motor.

Regardless of the position of the switch, that is, whether it is in a horizontal position, vertical position or inclined position, one or both yof the mercury slinger discs will operate as a pump to force mercury radially to the peripheral edges of one or both discs and thence across the passageway 34, the conduits 38, the annular channel 35, the passageway 36, and through the restricted opening 37 into the rotor recess 26. From the recess 26, the mercury is forced outwardly through the nozzle 31 and its orifice 32 as a jet or stream which successively contacts each of the adjacent ends of the contact terminal pins 33. The nozzle 31 therefore serves as a iirst pump to throw the mercury as a jet or stream into engagement with the contact terminals, and the discs 28 and 29 serve as Second Vpump elements to return the mercury to the rotor recess 26. The restricted opening 37 limits the flow of mercury through the conduit 38, thus preventing the complete drainage of the annular channels 9 and 11. Mercury is kept rotating around the annular channels 9 and -11 by the viscous drag ofthe rotating slinger discs 28 'and v29. 'Centrifugal force created by the rotating mercury manitains pressure on the mercury moving through the conduits 34 and 38.

The oriiice 32 being smaller than the restricted opening 37 drains mercury from the annular recess 26 at a lrate lower than the reiill rate through opening 37 thereby desired speed, the centrifugal force imparted by them to the mercury can be made substantially greater than gravity or any conceivable number of Gs to which the switch could be subjected even when carried by a jet plane or rocket.

Here it should also be noted that since the bearing bushing 13 and the rotor 25 are made of metal, they serveto complete the electric circuit Vbetween the mercury jet, the contact pins 33, and the lead 44.

It should also be observed that due to the construction and operation yof the switch, no mercury is at any time allowed 'to stand in a static pool, but instead is always kept in motion. In effect: the mercury is dynamically isolated at the outer periphery of both the stator (casing) and the rotor.

It is of course contemplated that all of. the rotating members of the switch be dynamically balanced in accordance with usual practice.

I claim:

l. A mercury jet switch comprising: a casing provided with first and second spaced, parallel, annular channels circumscribing and in open communication with a central chamber; a rotor journalled in said central chamber coaxially with said annular channels and provided with an internal annular recess; an outwardly extending nozzle mounted on said rotor in communication with said annular recess; a ring of spaced contact terminals mounted on the peripheral Wall of said central chamber adjacent the locus of said nozzle and in alignment therewith; first and second mercury slinger discs mounted on said rotor and extending,7 respectively into said first and second vannular channels; and a conduit extending between the. peripheral edges of said first and second annular channels and communicating with said annular' recess.

2. A switch such as defined in claim l, wherein said Contact terminals are Vmounted in an Ainwardly extending annular ilange formed `substantially centrally of said casing.

No references cited. 

